This invention relates to electronic systems which receive data via channels of sensing circuitry and cause such data to be subsequently processed to provide desired information.
Such systems for receiving and processing information may combine a sensing portion having space and/or power limits, with a remote processing portion communicating with the sensing portion. For example, the sensing portion may be onboard an aircraft or satellite, while the processing portion may be on the ground, where power and space are not significantly limited.
Some of the work leading to the present invention was motivated by a program to detect lightning pulses, which may predict the occurrence of tornadoes. Other event (i.e., random event) detection systems might be used to watch for nuclear events, or to observe moving objects. Numerous uses are possible in commercial situations, such as observation of manufacturing processes in order to sense the occurrence of certain random events, after which the data on such events is fed to a control computer to provide process information and control.
A primary problem in such a signal sensing and signal processing system is that it may have many parallel sensing inputs, and only a few output channels leading to the processing electronics. For example, an IC chip might have 64 input channels and 4 output channels, a ratio of 16. The ratio might be pushed substantially higher. If a focal plane 3D stack of IC chips is used, such as the stack described in common assignee U.S. Pat. No. 4,551,629, the total number of input channels might be 64.times.64 (4,096); and the total number of output channels might be 64.times.4 (256).
Heretofore, input signals from high density sensing structures have been transferred to the processing circuitry by means of conventional multiplexers. A conventional time division multiplexer receives the parallel input signals, and, based on clock intervals, sends them serially in a predetermined order to an output channel. The maximum available bandwidth is a function of the time required for all the sensing channels to be sampled via the multiplexer output channel to which their signals are directed. In the example of 16 sensing channels for each multiplexer output channel, the bandwidth would be 1/16 of the clock frequency.
An important purpose of the present invention is to significantly enhance available bandwidth in a signal sensing and switching system. A related purpose is to improve the ability of such a system to separate signals of interest from undesired background signals, thereby increasing dynamic range.